The invention relates generally to a method and apparatus for releasing a gaseous material into the atmosphere. More specifically, the invention relates to such a method and apparatus wherein a gaseous material is sorptively stored on a sorbent material, which is then selectively exposed to the atmosphere in order to cause such gas release. As used herein, the terms "sorbent" or "sorptive", or the like, refer to the use of either the use of an adsorbent or an absorbent.
Various devices have been provided for releasing a material, such as an odorant, an insect repellent, or an antiseptic or other medicinal substances into the atmosphere in order to create a pleasant odor, an insect-free region, or other beneficial atmospheric conditions. Typically such previous devices have included wicks or other such media onto which the material has been placed and allowed to be released into the atmosphere by an evaporation process. In other instances, the released material has been discharged into the atmosphere by a technique in which a water vapor released into the atmosphere serves as a carrier for the material. Typically, however, such previous devices have only been capable of storing a relatively small amount of the material to be released into the atmosphere, and thus have been relatively short-lived, requiring frequent replacement, maintenance, or recharging. In addition, such devices that use a released water vapor as a carrier for discharging the material into the atmosphere have required relatively expensive and complex vapor-producing mechanisms, which also require frequent maintenance and recharging with the material to be released.
In light of the above-discussed state-of-the-art, one of the object of the present invention is to provide an apparatus and method for releasing a gaseous material into the atmosphere in a predetermined, relatively controlled, concentration level, and which is capable of storing relatively large amounts of the released material in order to significantly lengthen the useful life of the apparatus. In addition, another object of the present invention is to provide such a method and apparatus that does not require the use of relatively expensive, complex, or high-maintenance mechanisms.
In accordance with the present invention, an apparatus for releasing gaseous material into the atmosphere employs a sorbent material that is sorptively saturated with a predetermined quantity of the gaseous material at a predetermined pressure, preferably approximately equal to atmosphere pressure. The gaseous material to be released preferably has a vapor pressure lower than the predetermined pressure at which the sorbent material is sorptively saturated. The apparatus also includes means for selectively exposing the sorbent material to the atmosphere in order to allow the gaseous material to be desorptively released.
In a preferred form of the apparatus and method according to the present invention, the sorbent material is first depressurized to a pressure lower than the predetermined saturation pressure level prior to being sorptively saturated with the gaseous material. Preferably the sorbent material is heated during such depressurization in order to more effectively clear the sorbent material of undesirable sorbed contaminants or other substances, thereby increasing the sorptive storage capability of the sorbent material for the desired gaseous material to be released to the atmosphere.
Additional objects, advantages, and features of the present invention will become apparent from the following description and the appended claims, taken in conjunction with the accompanying drawings.